Rotary switch assembly with printed circuit rotor and multilayer housing features

ABSTRACT

A rotary switch is provided which is adaptable for being stacked in multiple layers for multi-function use by a single control shaft. A printed circuit board and a brush member are supported in a dust-proof housing in contacting relation and means are provided for rotating one of the board and the brush relative to the other to any of a predetermined number of distinct positions. Additionally, the inputs and outputs of the switch are all aligned in a single plane.

I United States Patent 91 1 3,736,390 Lockard 1 Ma 29 1973 [54] ROTARYSWITCH ASSEMBLY WITH 3,504,139 3 1970 Long ..200 11 TW PRINTED CIRCUITROTOR AND :1 1: p ZOO/66 SD X aine et a MULTILAYER HOUSING FEATURES2,894,096 7/1959 Schacht ..200/11 G X [75] Inventor: Joseph LaRu'eLockard, Harrisburg, 3,478,180 11/1969 Bang ..200/14 X Pa. PrimaryExaminer-J. R. Scott I [73] Assignee: AMP Incorporated, Harrisburg, Pa.w Grefe 22 Filed: Dec. 10,1971 Gerald Klta 2 [21] Appl No 06,665ABSTRACT [52] U 8 Cl 200/ DA 200/14 200/ G A rotary switch is providedwhich is adaptable for 200/l66 CT zoo/I68 being stacked in multiplelayers for multi-function use [51 I Cl 01h 19/58 iiolh 21/78 by a singlecontrol shaft. A printed circuit board and a i 200/11 14 166 SD brushmember are supported in a dust-proof housing 1 8 K 1 1 3 H K 1 incontacting relation and means are provided for l v G 1 T rotating one ofthe board and the brush relative to the other to any of a predeterminednumber of distinct v positions. Additionally, the inputs and outputs ofthe [5 6] References cued switch are all aligned in a single plane.

UNITED STATES PATENT-S 32 Claims, 11 Drawing Figures 3,558,834 l/l97lZielke ..200/11 TW Patented May 29, 1973 3,736,390

2 Sheets-Sheet 1 Patented May 29, 1973 2 Sheets-Sheet 2 ROTARY SWITCHASSEMBLY WITH PRINTED CIRCUIT ROTOR ANI) MULTILAYER HOUSING FEATURESBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates generally to rotary switches and more particularly toan improved multilayer rotary switch of compact construction forhighdensity switch applications.

2. Prior Art In the past, rotary switches have been bulky and heavyusually hand-constructed items which were difficult to wire and weresubject to being easily damaged if accidentally dropped, or even by dustand dirt in the storage or operational environments thereof entering theswitch housing and causing short-circuiting to occur therein. Theseformer switches accordingly were not entirely satisfactory forhigh-density applications for these reasons, but more primarily becauseof their size which normally precluded the use of a plurality of suchswitches being used together to accomplish multiple functionssimultaneously and because the inputs and outputs thereof were notaligned, such that a large area was needed to provide suitableconnections thereto. With the advent of integrated and miniaturizedcircuits, a need now exists for a compact and compatible rotary switchcapable of satisfying the requirements incidental thereto.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a novel and improved rotary switch of compactconstruction for use in high-density switch applications.

Another object of the present invention is to provide a rotary switchwhich is compact, easily assembled at low cost, and yet which is notreadily subject to being damaged.

Still another object of the present invention is to provide a rotaryswitch being encapsulated to prevent access of dust or dirt and therebybeing substantially safe from being short-circuited therewithin.

Yet another object of this invention is the provision of a rotary switchof compact construction designed to facilitate stacking with likeswitches to permit an increased number of functions to be performedthrough operation of a single control knob in a minimum amount of space.

A further object of the invention is the provision of .a compact codedrotary switch which is dust-proof, less complex and expensive tomanufacture than present coded switches, less subject to damage, andbeing readily coupled in stacked relation with similar switches toincrease the number of functions which may be performed through a singlecontrol in a minimum amount of space.

Yet a further object of this invention is the provision of a compactdecimal version rotary switch being dust proof and not readily subjectto damage, and being stackable with similar switches to permit anincreased number of functions to be performed through operation of asingle control shaft, while having minimum space requirements. t

The foregoing and other objects are attained according to one aspect ofthe present invention by a rotary switch, the parts of which generallyare composed of plastic materials, comprising a coded printed circuitboard rotatably disposed in a given plane in a dustproof housing, aplurality of elongate brush members associated therewith being fixedlysecured in the housing so that the brush end thereof is always pressedagainst the printed circuit board with the other end extending from thehousing and lying in the same plane as the board, and an operating shaftprojecting from the housing being perpendicularly oriented relative tothe printed circuit board and connected thereto for rotating the samefrom outside the housing. Within the housing, the operating shaft isconnected to the printed circuit board through a disc-like memberpositioned on the shaft in parallel relation with the board for beingrotated therewith in conjunction with the board and having compressibletabs formed on the periphery thereof which engage a plurality of detentsformed in a circular pattern on an inside wall portion of the housing,whereby the shaft may be turned to place the rotatable printed circuitboard in a plurality of distinct positions wherein different codingfunctions are established between the printed circuit on the board andthe brushes. The housing exterior is further designed so that aplurality of the housings may be readily secured together in anend-to-end, or stacked, relation such that a corresponding plurality ofprinted circuit boards may be simultaneously rotated by a singleoperating shaft projecting through all of the housings to increase thenumber of functions that may be accomplished by maneuvering a singlecontrol knob.

In another aspect, the rotary switch of the present invention isembodied in a decimal version, wherein a fixed printed circuit board isprovided within the housing and a brush member connected to theoperating shaft is rotatably disposed thereon.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features andattendant advantages of the present invention will be more fullyappreciated as the same becomes better understood from the followingdetailed description when considered in connection with the accompanyingdrawings, in which like reference characters designate like orcorresponding parts throughout the several views, and wherein:

FIG. 1 is an exploded perspective view of a switch constructed accordingto the present invention illustrating the arrangement of the variouselements thereof in which they will be assembled, including the housing,a coded printed circuit board, a plurality of brushes associatedtherewith within the housing and a control shaft designed for rotatingthe coded printed circuit board;

FIG. 2 is a perspective view of the interior of one end cover of thehousing shown in FIG. 1, illustrating the detents formed therein, and aninternal gear adapted to be disposed therewithin for rotary movementbetween these detents;

FIG. 3 is a perspective view of the interior of another embodiment of ahousing end cover, similar to that shown in FIG. 2, but being providedwith stop members for preventing full revolution of the control shaft;

FIG. 4 is a side elevational view in cross section of the switchillustrated in FIG. 1 being shown in its assembled condition, with acontrol knob affixed to the projecting end of the control shaft;

FIG. 5 is a sectional view of the switch shown in FIG. 4, taken alongthe line AA thereof, wherein the detented housing end cover of FIG. 2 isemployed;

FIG. 6 is a sectional view of the assembled switch shown in FIG. 4 takenalong the line AA thereof, wherein the detented housing end cover havingstop members integrally formed therein is employed;

FIG. 7 is a perspective view of a stacked array of a plurality of theswitch assemblies illustrated in FIGS. 1 and 4;

FIG. 8 is a side view of a portion of the switch shown in FIGS. 1 and 4,illustrating one manner of providing an electrical connection to aterminal of a brush member thereof;

FIG. 9 is a perspective view illustrating another manner of providingelectrical connection to the terminals of the brush members of theswitch shown in FIG. 1, wherein the pin sections thereof are bent backto receive posts;

FIG. 10 is an exploded perspective view of another embodiment of aswitch constructed according to the present invention, wherein a decimalversion printed circuit board is provided; and

FIG. 11 is a side elevational cross-sectional view of a portion of theswitch illustrated in FIG. 10, showing the connection of a circularspring-like brush member to the printed circuit board thereof.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring-now to thedrawings, and more particularly to FIG. 1 thereof, a housing for theswitch of the present invention is shown being composed of threeseparate pieces, preferably constructed of a plastic material either bymolding or stamping, and including an end cover member 10, a centralbrush housing member 11 and an opposing end cover member 12, each havinga flat planar portion configuration so that when the pieces areassembled they define a flat planar portion on the switch as illustratedin the drawings.

The end cover member 10 is provided with a circular upstanding rib 13which is adapted to be received in a mating hollow recess 14, shown inFIG. 4, of the central housing member 11, and with a plurality ofindentations 15 along the interior of the bottom edge thereof forreceiving corresponding projecting tabs 16 of the central housing member11, also shown in FIG. 4, during assembly of the central housing member11 onto the end cover member 10. A central recess 17 is also provided inthe end cover member 10 for receiving a disc member 18 preferablyconstructed of a plastic material, the purpose of which will bedescribed later. As shown in FIG. 1, the disc member 18 is formed with acentral opening 19 having a square cross-sectional configuration.

A flat circular printed circuit board member 20 having a coded circuitetched on one face thereof is positioned in the recess in the end covermember 10 defined by the upstanding rim 13 thereof. The printed circuitboard 20 also is provided with a central throughopening of asquare-shaped configuration.

In assembling the switch, the central housing member 11 next ispositioned on the end cover member 10 with the tabs 16 thereof beinginserted into the indentations 15 as previously described. The rim 13registers within recess 14. As shown in FIG. 4, the end cover 10includes an annular rim 21 radially spaced of the rim 13 against whichthe circuit board 20 abuts. The housing member 11 includes an annularrim 21 which is similar to and in opposing relationship to the rim 21when the cover 10 and housing member are assembled. The rims 21 and 21cooperate to abut and retain the circuit board 20 therebetween, and toprevent warpage of the circuit board. The rims 21 and 21 are alsorelatively thin so as to provide bearing surfaces of relatively smallareas upon which the circuit board is supported for relatively lowfriction slidable rotation. The yet open end of the central housingmember 11 also is provided with an upstanding rib member 22 which isadapted to be received in a mating recess in the opposing end cover 12whenassembled. In addition, a central diametrical opening 23 is providedin the central housing member 11 for permitting access of brush contactmembers 24 to the printed circuit board 20. As illustrated in FIG. 1,the brush members 24 are formed as curved portions on the ends ofcarrier strip tabs 25 of a special configuration, being elongate innature and having a right-bend 26 formed therein intermediate the lengththereof and a wire-receiving piece 27 at the other end. To accommodatethe carrier strip tabs 25, the central brush housing member 11 has aplurality of parallel grooves 28 formed therein, each having a block 29which is adapted to fit within the bend 26 of a carrier strip tab beingreceived in the groove. Thus, when the carrier strip tabs 25 are placedinto the grooves 28, the bends 26 are placed over the blocks 29 so thatthe curved brushes 24 lie in contact with the printed circuit board 20and the wire-receiving pieces 27 protrude through the flat planarportion of the switch.

Next, a control shaft 30 having an axial squareshaped opening in one endthereof for receiving a rod 31 of square cross-section is projectedthrough a central opening in the end cover member 12. On the interiorsurface of the end cover member 12, a recess 32 is formed, as shown inFIG. 2, the periphery of which is somewhat tooth-shaped to provide aplurality of detents 33 for engagement by a gear member 34. The gearmember 34 is a substantially ring-shaped piece having a diametrical arm35 in which a squareconfigured central opening 36 is provided, and apair of diametrically opposed projecting tabs 37 on the outer peripherythereof which are receivable in the detents 33 and are compressible tosuch an extent to permit being snapped from one set of detents to anadjacent set of detents upon rotation of the gear member 34. Thus, thedetent control 33 and the housing mem ber 12 are of one piececonstruction for compactness and for elimination of a plurality ofseparate parts to simplify assembly.

The end cover members 12 having the gear member 34 disposed in therecess 32 thereof fits onto the central brush housing member 11, withthe projecting circular rib 22 of the central member 11 being receivedin an annular groove 38 formed about the detentedrecess 32 of outer endcover member 12. When positioned together in this manner, thesquare-configured rod 31 projects loosely through the opening 23 in thecentral brush housing member 11, and tightly fits within thecorresponding square-configured openings in the printed circuit board 20and the disc member 18, so that any rotation imparted to the controlshaft 30 is operable to cause rotation of the printed circuit board 20therewith. The shaft 30 thus provides an axis of rotation about whichthe printed circuit board 20 is rotatably displaceable. Simultaneously,of course, the gear 34 is rotated when a sufficient turning force isprovided for snapping the projecting tabs 37 between adjacent sets ofdetents 33.

A plurality of projecting tabs 39 formed on the interior surface of theopposing end cover member 12 along the bottom edge thereof are adaptedto fit within the lower part of grooves 28 in the central brush housingmember 11, below the blocks 29 therein, when the cover members areassembled. An upper set of aper- .tures 40, 40 and 40 are respectivelyprovided in the housing members 10, 11 and 12, as are lower sets ofapertures 41, 41', 41" and 42, 42 and 42", for the purpose of securingthe housing members together by suitable means, such as bolt and nutconnection. In this manner, when so assembled, it may be seen that adust- .proof housing for enclosing the switch contact elements isprovided.

Turning to FIG. 4, wherein the assembled switch is illustrated beingmounted on one side of a panel 43 with the control shaft 30 thereofprojecting through the panel, a nut 44 is shown being threaded onto anexternally threaded central projection 45 of the housing end cover 12for clamping the switch housing to the panel 43. An O-ring sealing means46 is shown surrounding the threaded portion 45 on one side of the panel43 and a suitable sealing washer 47 is provided on the other sidebetween the panel 43 and the securing nut 44. Disposed on the end of thecontrol shaft 30 is a control knob 48 having a suitably shaped recessfor receiving the end of shaft 30 which, as shown in FIG. 1, has anarcuate portion thereof cut away, so that rotation of the control knob48 with a sufficient force will rotate the control shaft 30 and causegear member 34 to move between distinct rotational positions defined bythe detents 33 and the projecting tabs 37, the relationship of which ismost clearly shown in FIG. 5.

In certain cases, it may be desirable to provide a switch of thecharacter described which is, for example,

limited to a number of preselected positions, and in such cases anotherembodiment of the housing end cover 12, as shown in FIGS. 3 and 6 may beprovided. The only distinction between this embodiment and thatpreviously described is that stop members 50 are integrally formed onthe interior surface of the housing end cover member 12 on the base ofthe recess 32 therein. Thus, when the control shaft 31 is rotatedthrough operation of the control knob 48, the gear member 34 is causedto turn and is limited in its degree of rotation by the diametrical arm35 coming into contact with one or the other of stop members 50. Asshown, rotation through approximately 180 is possible, since one-half ofthe diametrical arm 35 is formed being of reduced thickness, or cut awayon the surface thereof facing the interior. of the end cover 12 suchthat it is capable of passing freely over the stop members 50, whileonly the other portion of the arm 35-serves to preclude furtherrotation. It should be understood, therefore, where it is desirable topermit nearly complete revolution but to prevent passage through apredetermined zeroposition, only a single stop 50 need be provided inthe end cover 12.

The compact construction provided with the present invention readilypermits stacking of a plurality of the housings formed by the housingmembers 10, 11 and 12 in end-to-end relation, such as illustrated inFIG. 7, in which case if a different code were provided on each istersin the recess 14 of an adjacent stacked housing member 11 without a needfor any end cover or front cover 12 therebetween. Thus the rim 22 andthe rim 13 are of similar configuration for registration in a recess 14of any housing member 11. Also, the housing member 11 is provided with arelatively thin annular rim 21" similar to the rim 21 on the end cover10, so that when an end cover 10 is eliminated between two stackedhousing members 11, the rim 21" of one housing member 11 will cooperatewith the rim 2] of the other stacked housing member to slidably supporta circuit board 20 in the same manner as the board 20 is supported bythe rims 21 and 21 as shown in FIG. 4. Thus, between stacked housingmembers 11, the cover 10 can be eliminated, with an adjacent housingmember 11 performing the functions of the cover plate 10. This resultsin a compact assembly with the control shaft 31 being supported only atits ends, by one end cover 10 at one end, and by one housing member 12at the other end. With only one housing member 12 required, only onedetent control 33 is needed for an entire assembly of stacked circuitboards 20.

Turning now to FIGS. 8 and 9, there are shown different methods ofelectrically connecting the brushes 24 exteriorally of the housing whichmay be employed with the compact and unique construction of the presentinvention. In FIG. 8, for example, an electrical wire may be bent in aconventional manner and inserted into the wire-receiving piece 27 of thecarrier strip tabs 25, which then is compressed thereabout. In FIG- 9,however, the wire-receiving pieces 27 are shown being bent back forreceiving terminal posts, such that a plug-in adaptation would bepossible. It is noted, in this respect, that the inputs and outputs, orall of the carrier strip tabs 25, are positioned inone plane tofacilitate plugging the same into a printed circuit board.

Another embodiment of the present invention is illustrated in FIGS. 10and 11, wherein a decimal version is provided. In this embodiment, ahousing member 51 provides a recess 52 for receiving a printed circuitboard 53, with a tab 54 projecting from the recess 52 being engaged withan aperture 55 in the printed circuit board. A thin disc-like piece 56having a central square-configured opening and a plurality of pinsprojecting from one face thereof is fixed to one face of the printedcircuit board 53 with the pins thereof extending through a centralopening 57 in the board being received in corresponding pin openings ina thin washer element 58 on the printed circuit side of the board 53. Aring brush member 60 is engaged between the washer member 58 and a plug61 havingv a central post extending through an opening of the brush ring60 and a base member having pin openings therein for receiving the pinsof the disc member 56 and extending through the washer member 58. Thebase and post portions of the plug member 61 are provided with acontinuous through opening of square configuration for receiving acontrol shaft 31 of the type described hereinbefore. The brush ring 60accordingly is rotatably fixed on the printed circuit board 53.

Referring more particularly to FIG. 11, the brush ring 60 is shownhaving arcuate arms 62 and 63 extending in opposite circumferentialdirections which are bent in the direction of the printed circuit boardso that the ends thereof engage the board. The one arm 62 is at a lesserradial distance from the brush ring center than the other arm 63, suchthat it is always in engagement with an annular conductive area 64 onthe board 53 positioned about the central opening 57 therein. The otherarm 63 is adapted upon rotation of the brush ring 60 to engage adifferent one of a plurality of conductive areas 65 on the printedcircuit board, whereby different circuits may be connected according tothe rotating of the control shaft to preselected different rotarypositions.

With this embodiment, an end cover, not shown, must be provided on theside of the housing member 51 opposite the printed circuit board 53, andanother end cover 66 having the same detent and internal geararrangement as described above must be provided for the printed circuitboard side of the housing member 51. These end covers must of course bedifferent than the end covers 10 and 12 above, especially along thebottom edges thereof, so that they conform to the housing member 51 toprovide a dust-proof enclosure. Obviously, the outputs of the printedcircuit board 53 may be made for plugging the same into a printedcircuit board or they could be provided with spaced tabs for breakingconventional wire connections.

With the embodiments described hereinabove, it should be clear that theobjects of this invention have been achieved. Further, in order to varythe code of any of the switches described herein, it is only necessaryto change the printed circuit board, which may be accomplished at thetime of manufacture. The number of detent positions is determined by thecode, or the design of the conductive area of the printed circuit board.Because of the plastic material used in manufacturing the parts, theswitch is less susceptible to damage, and its novel arrangement ofelements makes the switch more adaptable to various applications, whileat the same time being very compact.

Obviously, many modifications and variations are possible in light ofthe above teachings. It is to be understood, therefore, that within thescope of the appended claims the invention may be practiced otherwisethan is specifically described herein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In a switch having a housing, a printed circuit board mounted fordisplacement in said housing, at least one electrical contact protruding,extemally of said housing and having a brush portion protruding intosaid housing and engaging said printed circuit board for electricalengagement on a selected electrical circuit provided on said printedcircuit board upon displacement of said printed circuit board, and meansmounted in said housing for displacing said printed circuit board, theimprovement comprising: a pair of bearing surfaces fixedly located onsaid housing and abutting and supporting opposite sides of said printedcircuit board and retaining said circuit board therebetween andpreventing warping of said printed circuit board.

2. The structure as recited in claim 1, wherein said printed circuitboard is displaceable about, an axis of rotation, said bearing surfacesare circular rims, said rims encircle and axis of rotation of saidprinted circuit board, and said rims abut and support said printedcircuit board circularly about its axis ofrotation to prevent warping ofsaid printed circuit board.

3. The structure as recited in claim 2, wherein, said rims arerelatively thin to provide bearing surfaces of relatively small areasupon which the printed circuit board is slidably supported forrelatively low sliding friction.

4. The structure as recited in claim 1, and further including: at leastone additional electrical contact protruding externally of said housingand having a brush portion protruding internally into said housing andengaging said printed circuit board for selective electrical engagementwith a selected electrical circuit provided on said printed circuitboard.

5. The structure as recited in claim 4, wherein, said housing has a flatplanar portion, and all of said electrical contacts protrude from saidhousing only through said flat planar portion for making electricalconnections externally of said housing.

6. The structure as recited in claim 4, wherein, said housing includesan internal detent portion, and further including: a gear mounted insaid housing for selective engagement in said detent portion, therebypositively locating said printed circuit board in selected positionsdetermined by selective engagement of said gear in said detent portion.

7. The structure as recited in claim 1, wherein, said housing includesdetent means, and further including: a gear mounted in said housing fordisplacement and having a portion displaceable into selected engagementin said detent means, thereby positively locating said printed circuitboard in a selected positions defined by the selected engagement of saidgear in said detent means.

8. The structure as recited in claim 4, wherein, said electricalcontacts include electrical wire-receiving portions protrudingexternally of said housing for making electrical connections externallyof said housing.

9. The structure as recited in claim 4, wherein, said housing includes afirst member having grooves each receiving one of said electricalcontactstherein, said grooves each having a shape conforming to theshape of a corresponding electrical contact for registration of thecorresponding electrical contact fixedly in position within the groove,and a cover overlying said first member with said electrical contactsinterposed between said first member and said cover, whereby saidelectrical contacts are fixedly retained with respect to said housing.

10. A switch, comprising: a first brush housing mem-' ber of electricalinsulation material having aplurality of electrical contacts mountedthereon, said contacts further having electrical terminal portionsprotruding externally of said brush housing member formaking desiredelectrical connections externally of said brush housing member, a firstprinted circuit board having electrical circuits thereon, said contactshaving brush portions protruding internally of said brush housing memberand engaging said printed circuit board, a first cover portion engagingand covering one end of said brush housing member, said first printedcircuit board being enclosed by and interposed between said first coverportion and said brush housing member, said first cover portionincluding a support means engaging said printed circuit board, saidbrush housing member 'having a first bearing surface engaging saidprinted circuit board and cooperating with said support means to supportsaid printed circuit board therebetween and thereby prevent warpage ofsaid printed circuit board, covering means covering another end of saidbrush housing member, and displacing means mounted on said switch fordisplacing said first printed circuit board relative to said brushportions for engagement of said brush portions with selected electricalcircuits on said first printed circuit board, said first printed circuitboard being slidably displaceable relative to said support means andsaid first bearing surface.

11. The structure as recited in claim 10, wherein, said covering meansincludes a second brush housing member abutting said first brush housingmember, a second printed circuit board interposed between said first andsaid second brush housing members, said second printed circuit boardbeing provided with electrically conducting circuit paths thereon,electrical contact means in said second brush housing member, saidsecond printed circuit board being displaceable relative to saidelectrical contact means to enable selected electrical engagement ofsaid electrical contact means with selected electrically conductingcircuit paths on said second printed circuit board, said first brushhousing member having a second bearing surface engaging said secondprinted circuit board, said second brush housing member having bearingsurface means engaging said second printed circuit board and cooperatingwith said second bearing surface of said first brush housing member tosupport therebetween said second printed circuit board and to preventwarpage of said second printed circuit board, said second printedcircuit board being slidably displaceable by said displacing meansrelative to said second bearing surface and said bearing surface means.

12. The structure as recited in claim 10, wherein, said first printedcircuit board is rotatably displaceable about an axis of rotation, saidfirst bearing surface is in the form of a circularrim encircling saidaxis of rotation, and said rim is of relatively thin configuration tominimize the bearing surface area thereof engaging said first printedcircuit board and to minimize sliding friction resulting fromdisplacement of said first printed 'circuit board relative to' said rim.

13. The structure as recited in claim 10, wherein, said first printed Icircuit board is rotatably displaceable about an axis of rotation, saidsupport means is in the form of a circular rim encircling said axis ofrotation, and said rim is of relatively thin configuration to minimizethe bearing surface area thereof engaging said first printed circuitboard and to minimize the sliding friction resulting from displacementof said first printed circuit board relative to said rim.

14. The structure as recited in claim 10, wherein, said first printedcircuit board is rotatably displaceable about an axis of rotation, andsaid support means and said first bearing surface are in the respectiveforms of circular rims encircling the axis of rotation of said firstprinted circuit board, said circular rims being of relatively thinconfigurations to minimize the bearing surface areas engaging said firstprinted circuit board and to minimize sliding friction resulting fromdisplacement of said first printed circuit board relative to said rims.

15. The structure as recited in claim 10, wherein, said brush housingmember is provided with grooves each receiving one of said electricalcontacts therein, each of said grooves having a shape corresponding tothe shape of a corresponding electrical contact for registration of thecorresponding electrical contact fixedly in position within the groove,said electrical contacts being interposed between said brush housingmember and said covering means, whereby said electrical contacts arefixedly retained with respect to said brush housing member.

16. The structure as recited in claim 1 1, wherein, said first printedcircuit board is rotatably displaceable about an axis of rotation, andsaid support means and said first bearing surface are in the respectiveforms of circular rims encircling the axis of rotation of said firstprinted circuit board, and said circular rims are of relatively thinconfigurations to minimize the bearing surface areas engaging said firstprinted circuit board and to minimize the sliding friction resultingfrom displacement of said first printed, circuit board relative to saidrims.

17. The structure as recited in claim 1 1, wherein, said first printedcircuit board is rotatably displaceable about an axis of rotation, saidsupport means is in the form of a circular rim encircling said axis ofrotation, and said rim is of relatively thin configuration to minimizethe bearing surface area thereof engaging said first printed circuitboard and to minimize the sliding friction resulting from displacementof said first printed circuit-board relative to said rim.

18. The structure as recited in claim 1 1, wherein, said first printedcircuit board is rotatably displaceable about an axis of rotation, saidfirst bearing surface is in the form of a circular rim encircling saidaxis of rotation, and said rim is of relatively thin configuration tominimize the bearing surface area thereof engaging said first printedcircuit board and to minimize the sliding friction resulting fromdisplacement of said first printed circuit board relative to said rim.

19. The structure as recited in claim 1 1, wherein, said switch isprovided with detent means, and said displacing means is provided with agear displaceable into selected engagement within said detent means forlocating said first and said second printed circuit boards in selectedpositions defined by the selected engagement of said gear within saiddetent means.

20. The structure as recited in claim 19, wherein, said switch includesa projecting stop member, and said gear member is engageable againstsaid stop member to limit displacement of said gear member.

21. The structure as recited in claim 11, wherein, said first brushhousing member includes a plurality of grooves each receiving one ofsaid electrical contacts therein, said grooves each having a shapeconforming to the shape of a corresponding electrical contact forregistration of the corresponding electrical contact fixedly in positionwithin the groove, and said covering means overlying said first brushhousing member with said electrical contacts generally interposedbetween said first brush housing member and said covering means wherebysaid electrical contacts are fixedly retained with respect to said firstbrush housing member.

22. The structure as recited in claim 1 1, wherein, said brush housingmember, said first cover portion and said covering means define on saidswitch a planar portion, and said electrical contacts and saidelectrical contact means protrude from said planar portion formakingelectrical connections externally of said switch.

23. The structure as recited in claim 1 1, wherein, said second brushhousing member includes a plurality of grooves receiving said electricalcontact means therein, said grooves having shapes conforming to theshapes of said electrical contact means for registration of theelectrical contact means fixedly in positions within the grooves, and'means overlying said second brush housing member with said electricalcontact means generally interposed between said second brush housingmember and said lastmentioned means, whereby said electrical contactmeans are fixedly retained with respect to said second brush housingmember.

24. The structure as recited in claim 4, wherein, said electricalcontacts include pluggable portions for pluggable connection externallyof said rotary switch.

25. A rotary switch comprising: a housing; a printed circuit board; atleast one electrically conducting brush means; means for supporting saidprinted circuit board and said at least one brush means in contactingrelation within said housing; means for rotating said printed circuitboard to one of a predetermined number of distinct positions; a circulararray of detents formed in a plane on an interior surface of saidhousing; a gear disposed within said circular array of detents in thesame plane and having at least one projecting compressible tab forengaging in said detents; means connecting said gear and said printedcircuit board for providing simultaneous rotation thereof; means forrotating said gear from outside said housing; and said housing furthercomprising, one end cover for rotatably receiving said printed circuitboard therein, a brush housing member connectable with said one endcover in substantially dust-free relation and having means therein forsupporting the brush means with portions thereof extending therefrom ina common plane, another end cover connectable to said brush housingmember in substantially dust-free relation, means on said another endcover for connecting said housing on a panel with said means forrotating said printed circuit board projecting through said panel to aside thereof opposite said housing, and sealing means on said anotherend cover sealing said means for rotating said printed circuit board toprovide a substantially dust-free environment in said switch housing.

26. The structure as recited in claim 11, wherein said second printedcircuit board is rotatably displaceable about an axis of rotation, saidsecond bearing surface is in the form of a circular rim encircling saidaxis of rotation, and said rim is of relatively thin configuration tominimize the bearing surface area thereof engaging said second printedcircuit board and to minimize the sliding friction resulting fromdisplacement of said second printed circuit board relative to said rim.

27. The structure as recited in claim 11, wherein said second printedcircuit board is rotatably displaceable about an axis of rotation, saidbearing surface means is in the form of a circular rim encircling saidaxis of rotation, and said rim is of relatively thin configuration tominimize the bearing surface area thereof engaging said second printedcircuit board and to minimize the sliding friction resulting fromdisplacement of said second printed circuit board relative to said rim.

28. The structure as recited in claim 11, wherein said second printedcircuit board is rotatably displaceable about an axis of rotation, saidbearing surface means and said second bearing surface are in therespective forms of circular rims encircling said axis of rotation, andsaid rims are of relatively thin configurations to minimize the bearingsurface areas thereof engaging said second printed circuit board and tominimize the sliding friction resulting from displacement of said secondprinted circuit board relative to said rims.

29. The structure as recited in claim 10, wherein said brush housingmember, said first cover portion and said covering means define a flatplanar portion of said switch, said electrical contacts protrude fromsaid flat planar portion for making electrical connections externally ofsaid switch.

30. The structure as recited in claim 25, wherein said switch furtherincludes at least another brush housing member interposed between saidanother end cover and said means for supporting said printed circuitboard, a printed circuit means in said another brush housing member,electrical contact means in said another brush housing member havingbrush means contacting said printed circuit means, and said printedcircuit means being rotatable together with said printed circuit boardby said means for rotating said printed circuit board to one of apredetermined number of positions.

31. The structure as recited in claim 30, wherein said first-mentionedbrush housing member includes a first bearing surface abutting andslidably supporting said printed circuit board, said first-mentionedbrush housing member includes a second bearing surface slidably abuttingand supporting said printed circuit means, and said another brushhousing member includes a third bearing surface slidably supporting saidprinted circuit means.

32. The structure as recited in claim 30, and further includingadditional electrically conducting brush means mounted in said anotherbrush housing member and in contact with said printed circuit means.

1. In a switch having a housing, a printed circuit board mounted fordisplacement in said housing, at least one electrical contact protrudingexternally of said housing and having a brush portion protruding intosaid housing and engaging said printed circuit board for electricalengagement on a selected electrical circuit provided on said printedcircuit board upon displacement of said printed circuit board, and meansmounted in said housing for displacing said printed circuit board, theimprovement comprising: a pair of bearing surfaces fixedly located onsaid housing and abutting and supporting opposite sides of said printedcircuit board and retaining said circuit board therebetween andpreventing warping of said printed circuit board.
 2. The structure asrecited in claim 1, wherein said printed circuit board is displaceableabout an axis of rotation, said bearing surfaces are circular rims, saidrims encircle and axis of rotation of said printed circuit board, andsaid rims abut and support said printed circuit board circularly aboutits axis of rotation to prevent warping of said printed circuit board.3. The structure as recited in claim 2, wherein, said rims arerelatively thin to provide bearing surfaces of relatively small areasupon which the printed circuit board is slidably supported forrelatively low sliding friction.
 4. The structure as recited in claim 1,and further including: at least one additional electrical contactprotruding externally of said housing and having a brush portionprotruding internally into said housing and engaging said printedcircuit board for selective electrical engagement with a selectedelectrical circuit provided on said printed circuit board.
 5. Thestructure as recited in claim 4, wherein, said housing has a flat planarportion, and all of said electrical contacts protrude from said housingonly through said flat planar portion for making electrical connectionsexternally of said housing.
 6. The structure as recited in claim 4,wherein, said housing includes an internal detent portion, and furtherincluding: a gear mounted in said housing for selective engagement insaid detent portion, thereby positively locating said printed circuitboard in selected positions determined by selective engagement of saidgear in said detent portion.
 7. The structure as recited in claim 1,wherein, said housing includes detent means, and further including: agear mounted in said housing for displacement and having a portiondisplaceable into selected engagement in said detent means, therebypositively locating said printed circuit board in a selected positionsdefined by the selected engagement of said gear in said detent means. 8.The structure as recited in claim 4, wherein, said electrical contactsinclude electrical wire-receiving portions protruding externally of saidhousing for making electrical connections externally of said housing. 9.The structure as recited in claim 4, wherein, said housing includes afirst member having grooves each receiving one of said electricalcontacts therein, said grooves each having a shape conforming to theshape of a corresponding electrical contact for registration of thecorresponding electrical contact fixedly in position within the groove,and a cover overlying said first member with said electrical contactsinterposed between said first member and said cover, whereby saidelectrical contacts are fixedly retained with respect to said housing.10. A switch, comprising: a first brush housing member of electricalinsulation material having a plurality of electrical contacts mountedthereon, said contacts further having electrical terminal portionsprotruding externally of said brush housing member for making desiredelectrical connections externally of said brush housing member, a firstprinted circuit board having electrical circuits thereon, Said contactshaving brush portions protruding internally of said brush housing memberand engaging said printed circuit board, a first cover portion engagingand covering one end of said brush housing member, said first printedcircuit board being enclosed by and interposed between said first coverportion and said brush housing member, said first cover portionincluding a support means engaging said printed circuit board, saidbrush housing member having a first bearing surface engaging saidprinted circuit board and cooperating with said support means to supportsaid printed circuit board therebetween and thereby prevent warpage ofsaid printed circuit board, covering means covering another end of saidbrush housing member, and displacing means mounted on said switch fordisplacing said first printed circuit board relative to said brushportions for engagement of said brush portions with selected electricalcircuits on said first printed circuit board, said first printed circuitboard being slidably displaceable relative to said support means andsaid first bearing surface.
 11. The structure as recited in claim 10,wherein, said covering means includes a second brush housing memberabutting said first brush housing member, a second printed circuit boardinterposed between said first and said second brush housing members,said second printed circuit board being provided with electricallyconducting circuit paths thereon, electrical contact means in saidsecond brush housing member, said second printed circuit board beingdisplaceable relative to said electrical contact means to enableselected electrical engagement of said electrical contact means withselected electrically conducting circuit paths on said second printedcircuit board, said first brush housing member having a second bearingsurface engaging said second printed circuit board, said second brushhousing member having bearing surface means engaging said second printedcircuit board and cooperating with said second bearing surface of saidfirst brush housing member to support therebetween said second printedcircuit board and to prevent warpage of said second printed circuitboard, said second printed circuit board being slidably displaceable bysaid displacing means relative to said second bearing surface and saidbearing surface means.
 12. The structure as recited in claim 10,wherein, said first printed circuit board is rotatably displaceableabout an axis of rotation, said first bearing surface is in the form ofa circular rim encircling said axis of rotation, and said rim is ofrelatively thin configuration to minimize the bearing surface areathereof engaging said first printed circuit board and to minimizesliding friction resulting from displacement of said first printedcircuit board relative to said rim.
 13. The structure as recited inclaim 10, wherein, said first printed circuit board is rotatablydisplaceable about an axis of rotation, said support means is in theform of a circular rim encircling said axis of rotation, and said rim isof relatively thin configuration to minimize the bearing surface areathereof engaging said first printed circuit board and to minimize thesliding friction resulting from displacement of said first printedcircuit board relative to said rim.
 14. The structure as recited inclaim 10, wherein, said first printed circuit board is rotatablydisplaceable about an axis of rotation, and said support means and saidfirst bearing surface are in the respective forms of circular rimsencircling the axis of rotation of said first printed circuit board,said circular rims being of relatively thin configurations to minimizethe bearing surface areas engaging said first printed circuit board andto minimize sliding friction resulting from displacement of said firstprinted circuit board relative to said rims.
 15. The structure asrecited in claim 10, wherein, said brush housing member is provided withgrooves each receiving one of said electrical contacts therein, eAch ofsaid grooves having a shape corresponding to the shape of acorresponding electrical contact for registration of the correspondingelectrical contact fixedly in position within the groove, saidelectrical contacts being interposed between said brush housing memberand said covering means, whereby said electrical contacts are fixedlyretained with respect to said brush housing member.
 16. The structure asrecited in claim 11, wherein, said first printed circuit board isrotatably displaceable about an axis of rotation, and said support meansand said first bearing surface are in the respective forms of circularrims encircling the axis of rotation of said first printed circuitboard, and said circular rims are of relatively thin configurations tominimize the bearing surface areas engaging said first printed circuitboard and to minimize the sliding friction resulting from displacementof said first printed circuit board relative to said rims.
 17. Thestructure as recited in claim 11, wherein, said first printed circuitboard is rotatably displaceable about an axis of rotation, said supportmeans is in the form of a circular rim encircling said axis of rotation,and said rim is of relatively thin configuration to minimize the bearingsurface area thereof engaging said first printed circuit board and tominimize the sliding friction resulting from displacement of said firstprinted circuit board relative to said rim.
 18. The structure as recitedin claim 11, wherein, said first printed circuit board is rotatablydisplaceable about an axis of rotation, said first bearing surface is inthe form of a circular rim encircling said axis of rotation, and saidrim is of relatively thin configuration to minimize the bearing surfacearea thereof engaging said first printed circuit board and to minimizethe sliding friction resulting from displacement of said first printedcircuit board relative to said rim.
 19. The structure as recited inclaim 11, wherein, said switch is provided with detent means, and saiddisplacing means is provided with a gear displaceable into selectedengagement within said detent means for locating said first and saidsecond printed circuit boards in selected positions defined by theselected engagement of said gear within said detent means.
 20. Thestructure as recited in claim 19, wherein, said switch includes aprojecting stop member, and said gear member is engageable against saidstop member to limit displacement of said gear member.
 21. The structureas recited in claim 11, wherein, said first brush housing memberincludes a plurality of grooves each receiving one of said electricalcontacts therein, said grooves each having a shape conforming to theshape of a corresponding electrical contact for registration of thecorresponding electrical contact fixedly in position within the groove,and said covering means overlying said first brush housing member withsaid electrical contacts generally interposed between said first brushhousing member and said covering means whereby said electrical contactsare fixedly retained with respect to said first brush housing member.22. The structure as recited in claim 11, wherein, said brush housingmember, said first cover portion and said covering means define on saidswitch a planar portion, and said electrical contacts and saidelectrical contact means protrude from said planar portion for makingelectrical connections externally of said switch.
 23. The structure asrecited in claim 11, wherein, said second brush housing member includesa plurality of grooves receiving said electrical contact means therein,said grooves having shapes conforming to the shapes of said electricalcontact means for registration of the electrical contact means fixedlyin positions within the grooves, and means overlying said second brushhousing member with said electrical contact means generally interposedbetween said second brush housing member and said lastmentioned means,whereby said electrical contact means Are fixedly retained with respectto said second brush housing member.
 24. The structure as recited inclaim 4, wherein, said electrical contacts include pluggable portionsfor pluggable connection externally of said rotary switch.
 25. A rotaryswitch comprising: a housing; a printed circuit board; at least oneelectrically conducting brush means; means for supporting said printedcircuit board and said at least one brush means in contacting relationwithin said housing; means for rotating said printed circuit board toone of a predetermined number of distinct positions; a circular array ofdetents formed in a plane on an interior surface of said housing; a geardisposed within said circular array of detents in the same plane andhaving at least one projecting compressible tab for engaging in saiddetents; means connecting said gear and said printed circuit board forproviding simultaneous rotation thereof; means for rotating said gearfrom outside said housing; and said housing further comprising, one endcover for rotatably receiving said printed circuit board therein, abrush housing member connectable with said one end cover insubstantially dust-free relation and having means therein for supportingthe brush means with portions thereof extending therefrom in a commonplane, another end cover connectable to said brush housing member insubstantially dust-free relation, means on said another end cover forconnecting said housing on a panel with said means for rotating saidprinted circuit board projecting through said panel to a side thereofopposite said housing, and sealing means on said another end coversealing said means for rotating said printed circuit board to provide asubstantially dust-free environment in said switch housing.
 26. Thestructure as recited in claim 11, wherein said second printed circuitboard is rotatably displaceable about an axis of rotation, said secondbearing surface is in the form of a circular rim encircling said axis ofrotation, and said rim is of relatively thin configuration to minimizethe bearing surface area thereof engaging said second printed circuitboard and to minimize the sliding friction resulting from displacementof said second printed circuit board relative to said rim.
 27. Thestructure as recited in claim 11, wherein said second printed circuitboard is rotatably displaceable about an axis of rotation, said bearingsurface means is in the form of a circular rim encircling said axis ofrotation, and said rim is of relatively thin configuration to minimizethe bearing surface area thereof engaging said second printed circuitboard and to minimize the sliding friction resulting from displacementof said second printed circuit board relative to said rim.
 28. Thestructure as recited in claim 11, wherein said second printed circuitboard is rotatably displaceable about an axis of rotation, said bearingsurface means and said second bearing surface are in the respectiveforms of circular rims encircling said axis of rotation, and said rimsare of relatively thin configurations to minimize the bearing surfaceareas thereof engaging said second printed circuit board and to minimizethe sliding friction resulting from displacement of said second printedcircuit board relative to said rims.
 29. The structure as recited inclaim 10, wherein said brush housing member, said first cover portionand said covering means define a flat planar portion of said switch,said electrical contacts protrude from said flat planar portion formaking electrical connections externally of said switch.
 30. Thestructure as recited in claim 25, wherein said switch further includesat least another brush housing member interposed between said anotherend cover and said means for supporting said printed circuit board, aprinted circuit means in said another brush housing member, electricalcontact means in said another brush housing member having brush meanscontacting said printed circuit means, and said printed circuit meansbeing Rotatable together with said printed circuit board by said meansfor rotating said printed circuit board to one of a predetermined numberof positions.
 31. The structure as recited in claim 30, wherein saidfirst-mentioned brush housing member includes a first bearing surfaceabutting and slidably supporting said printed circuit board, saidfirst-mentioned brush housing member includes a second bearing surfaceslidably abutting and supporting said printed circuit means, and saidanother brush housing member includes a third bearing surface slidablysupporting said printed circuit means.
 32. The structure as recited inclaim 30, and further including additional electrically conducting brushmeans mounted in said another brush housing member and in contact withsaid printed circuit means.